Agree--grade your paper...AND, don't buy "seconds" which is pulled out by quality control for being contaminated with a few particles of extra size. Yes, they put in random scratches and require backing up. My point on going to finer abrasives is this--practically start there. Some seem to me to take off too much wood when refinishing by assuming aggressive papers are required to take it down to new wood first. NOt! Steam out dents and perhaps scrape with glass first, then begin with six or eight hundred grit to just take the old finish down to the level of the wood. It will already be filled over much of the surface in that way. Less is more in by book. My biggest enemy is myself, so I constantly strive to practice restraint. Steve